MFJ MFJ-926B, Instruction Manual, Page: 16 / 20

MFJ-926B HF Automatic Remote Antenna Tuner Instruction Manual
 2010 MFJ Enterprises, Inc.
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4. Release the [TUNE] button. The unit then checks for short circuits, power-down detection level,
and wakeup circuitry.
5. Press [ANT] button and the green LED should blink once.
6. Press [TUNE] button and the green LED should blink once.
7. The unit then tests its non-volatile memory. Notice this step will reset the unit to its factory
default settings.
8. If the unit is okay, a repetitive message “PASS” will be sent in Morse code (di-dah-dah-dit di-dah
di-di-dit di-di-dit) by blinking the green LED. If there is a problem, a failure message will be sent
repetitively and the red LED will blink.
9. Turn the unit off, wait one second and turn the unit on again to test the power-down detection
circuitry.
10. If the power-down detection circuitry is okay, a repetitive message “PASS” will be sent in Morse
code (di-dah-dah-dit di-dah di-di-dit di-di-dit) by blinking the green LED. If there is a problem,
message “PD FAIL” will be sent as Morse code repetitively and the red LED will blink.
11. Turn the power off.
Failure
Message
Indicates
ANT FAIL [ANT] button is shorted or improperly connected.
TUNE FAIL [TUNE] button is shorted or improperly connected.
MEMORY FAIL Non-volatile memory circuitry is improperly connected.
WAKEUP FAIL Microprocessor wakeup circuitry problem.
PD FAIL Power-down circuitry problem.
Table 3. Failure Messages.
Power-Down Circuit Test
When the 12 VDC power to the tuner is turned off, the tuner saves all settings to non-volatile memory.
The Power-Down Circuit Test checks the power-down detection circuitry. It is recommended that this
test be done immediately after the regular self-test described above.
Note: The tuner must be reset to factory defaults before performing this test.
Here is the test procedure:
1. Make sure power to the tuner is off.
2. If the tuner has been reset to factory defaults, skip to step 6; otherwise continue with step 3.
3. Press and hold only the [ANT] button while turning the power on. Both LEDs will blink until the
button is released.
4. Within four seconds of releasing [ANT], press the [TUNE] button once.
5. After releasing [TUNE] for four seconds, Flash three times and turn the power off.
6. Press and hold only the [ANT] button while turning the power on. Both LEDs will blink until the
button is released.
7. Within four seconds of releasing [ANT], press the [TUNE] button four times.